1. Field of the Invention
The present invention relates to a signal reproducing apparatus and a signal reproducing method for reproducing a dynamic image by decoding coded image data which forms the dynamic image, and more particularly to a signal reproducing apparatus and a signal reproducing method for reproducing a plurality of dynamic images which have the same attributes.
2. Related Background Art
Optical disks have a common characteristic that random access is permitted. A DVD (Digital Video Disk: DVD-VIDEO) which is one of the optical disks uses the above-mentioned characteristic so that a multi-angle function and a multi-history function are realized.
The multi-angle function is a function for reproducing an image obtained by photographing the image at a plurality of shooting angles. For example, images of one subject at a plurality of angles can be reproduced.
The DVD uses angle blocks each of which is formed by data for enabling images at a plurality of angles to selectively be reproduced. The angle block is formed by sectioning image data photographed at each angle. The DVD employs a so-called "Interleave Structure" in such a manner that the angle blocks are mixed and then recorded on a signal recording surface. Since the DVD employs the foregoing recording structure, the multi-angle function and the multi-story function are realized.
A DVD reproducing apparatus is able to reproduce, for example, a DVD of the foregoing type in such a manner that switching to an image at a required angle is permitted during the reproducing process.
The angle block fall into two categories which is an angle block (hereinafter called "SML_AG_BLK") which can continuously, that is, seamlessly, connected to another angle when images which proceed simultaneously and other angle blocks (hereinafter called "NSML_AG_BLK") with which the angle can be switched only seamlessly.
When a process for reproducing SML_AG_BLK is performed, the DVD reproducing apparatus is able to seamlessly switch the angle. However, several seconds are required to switch the angle. That is, the DVD reproducing apparatus cannot reproduce another angle at the instant that the angle is switched. If a user switches the image which is being reproduced to that at another required angle, the user cannot watch the image at the required angle corresponding to the moment in time at which the angle is switched. As a result, the user cannot watch the required image. When SML_AG_BLK is reproduced, switching of the angle is limited to once in several seconds. Only sub-image data composed of audio data, subtitle information and the like corresponding to the image at the angle which is reproduced is encoded.
When NSML_AG_BLK is reproduced, the DVD reproducing apparatus must temporarily interrupt the reproducing operation when the angle is attempted to be switched. Then, the angle must be switched to another angle after which the reproducing process is restarted. In the case where angles are not smoothly connected to one another, the user cannot enjoy legible images.
When NSML_AG_BLK is reproduced, another angle corresponding to the moment in time at which the angle is switched can be reproduced. Moreover, switching is generally permitted in larger number of portions as compared with SML_AG_BLK. Even if an image is switched to an image at another angle, audio data and sub-image data individual from the image at the other angle can be decoded.
When NSML_AG_BLK and NSML_AG_BLK are reproduced, the DVD reproducing apparatus cannot immediately switch the angle in the seamless manner although it is able to simply switch the angle.
If images at various angles can simultaneously be provided for a user, the user is able to always confirm the images of the various angles. Thus, missing of a required image and image illegibility can be overcome. Therefore, there arises a requirement for an apparatus which is capable of simultaneously displaying images at a plurality of angles.